From 74ec02e9490d8aa086aa9ad9d1d34d2ad999b5af Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Sat, 8 Jul 2023 14:31:25 +0300
Subject: [PATCH] gh-106510: Fix DEBUG output for atomic group (GH-106511)

---
 Lib/re/_parser.py                                            | 4 +++-
 Lib/test/test_re.py                                          | 5 ++++-
 .../Library/2023-07-07-13-47-28.gh-issue-106510.9n5BdC.rst   | 1 +
 3 files changed, 8 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2023-07-07-13-47-28.gh-issue-106510.9n5BdC.rst

diff --git a/Lib/re/_parser.py b/Lib/re/_parser.py
index 6c8a4eccc0e0bb..22d10ab6e31d37 100644
--- a/Lib/re/_parser.py
+++ b/Lib/re/_parser.py
@@ -113,7 +113,6 @@ def __init__(self, state, data=None):
         self.width = None
 
     def dump(self, level=0):
-        nl = True
         seqtypes = (tuple, list)
         for op, av in self.data:
             print(level*"  " + str(op), end='')
@@ -135,6 +134,9 @@ def dump(self, level=0):
                 if item_no:
                     print(level*"  " + "ELSE")
                     item_no.dump(level+1)
+            elif isinstance(av, SubPattern):
+                print()
+                av.dump(level+1)
             elif isinstance(av, seqtypes):
                 nl = False
                 for a in av:
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index 8f26d0aacf4eee..b1699b0f83dbdd 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -2489,7 +2489,10 @@ def test_debug_flag(self):
 
     def test_atomic_group(self):
         self.assertEqual(get_debug_out(r'(?>ab?)'), '''\
-ATOMIC_GROUP [(LITERAL, 97), (MAX_REPEAT, (0, 1, [(LITERAL, 98)]))]
+ATOMIC_GROUP
+  LITERAL 97
+  MAX_REPEAT 0 1
+    LITERAL 98
 
  0. INFO 4 0b0 1 2 (to 5)
  5: ATOMIC_GROUP 11 (to 17)
diff --git a/Misc/NEWS.d/next/Library/2023-07-07-13-47-28.gh-issue-106510.9n5BdC.rst b/Misc/NEWS.d/next/Library/2023-07-07-13-47-28.gh-issue-106510.9n5BdC.rst
new file mode 100644
index 00000000000000..e0646fa9bc0211
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-07-07-13-47-28.gh-issue-106510.9n5BdC.rst
@@ -0,0 +1 @@
+Improve debug output for atomic groups in regular expressions.